600 pounds should be able to fish out good/great hardware, go for the CPU first. A high end i5 or i7 should do, then next on the list is the drive. For one of those you can either get a big enough SSD to run everything on or just buy it to hold the OS+your Minecraft contents then put everything else on a HDD. After that you will want some RAM, 8GB+ will do you well then you should be good to go.